Apparatus for automatically setting pins and detecting pinfall has been in use for many years in bowling alleys. Pinfall counting apparatus is used to give a relatively rapid indication of the number and location of pins standing after a ball has been rolled. The output of the apparatus may be provided to an automatic scoring system or may simply be used to assist the bowler in determining his score since visibility of the pins themselves is often limited.
At first, pinfall detection apparatus was mechanical or electromechanical in nature and was often incorporated into the pinsetting mechanism. Such apparatus typically used mechanical "fingers" or scanning bars to physically contact each pin after the pins had been picked up by the pin setting machine between balls.
Such electromechanical apparatus presented practical problems in that it often required an accurate alignment to initially calibrate the apparatus so it would operate properly under a variety of conditions. Thus, skilled installation personnel were required. The apparatus also continually required detailed maintenance to ensure that the apparatus remained both in alignment and operated properly in the severe environment of a typical bowling alley which includes mechanical shock and dirt. Furthermore, the apparatus was slow. More specifically, in the case of a strike, it was necessary to cycle the pinsetting machine before the apparatus could make the determination that all pins had fallen. This extra cycle lengthened the amount of time required to finish a bowling "string" and thus reduced the profit of the bowling alley operator. Finally, the apparatus could not be easily retrofit to equipment which was not originally designed for such apparatus.
Accordingly, other prior art schemes have been developed to produce pinfall count which do not use electromechanical sensors which must physically contact the pins. Typically these latter schemes rely on "active" scanning in which the pins are scanned by a light beam or an ultrasonic acoustic beam. The pins which are standing are counted by a transducer or a set of transducers which sense the echo or reflection of the scanning beam from the standing pins.
As with the prior electromechanical devices, these "active" scanning arrangements typically require a fairly accurate fixed alignment of the scanner and transducers with respect to the pins. The accuracy in alignment requires that skilled personnel be used to initially calibrate the equipment and also requires constant maintenance and long repair times if the apparatus fails.
Accordingly, it is an object of the invention to provide pinfall detection apparatus which does not use an active scanning mechanism.
It is another object of the present invention to provide a pinfall detection system which uses ambient light to illuminate the pins.
It is a further object of the present invention to provide a pinfall detection system which can be quickly and accurately aligned by ordinary maintenance personnel without requiring a high degree of skill or a detailed knowledge of the apparatus.
It is yet a further object of the present invention to provide a pinfall detection system which does not require constant maintenance and long repair times.
It is still another object of the present invention to provide a pinfall detection system which uses an ordinary video camera to detect pin presence or absence.
It is yet another object of the present invention to provide a pinfall detection system which utilizes a microprocessor to process the video image developed by the video camera to automatically total pincount and determine placement of the pins that remain standing.